#father {
  height: 400px;
  width: 400px;
  background-color: aquamarine;
  position: relative;
  /* display: flex;
  justify-content: center;
  align-items: center; */
  
}
#son{
  height: 100px;
  width: 100px;
  background-color: brown;
  /* transform: translate(-50%,-50%); */
  /* position: absolute;
  top: 0;
  bottom: 0;
  margin: auto;
  left: 0;
  right: 0; */
  left: 50%;
  top: 50%;
  position: absolute;
  /* transform: translateX(-50%) translateY(-50%); */
}